def test_assign_empty_list_no_event(self):
        """ assign empty list no event """

        a = PluginA()
        a.on_trait_change(listener, 'x_items')
        b = PluginB()
        c = PluginC()

        application = TestApplication(plugins=[a, b, c])
        application.start()

        # Assign an empty list to one of the plugin's contributions.
        b.x = []

        # Make sure we pick up the correct contribution via the application.
        extensions = application.get_extensions('a.x')
        extensions.sort()

        self.assertEqual(3, len(extensions))
        self.assertEqual([98, 99, 100], extensions)

        # Make sure we pick up the correct contribution via the plugin.
        extensions = a.x[:]
        extensions.sort()

        self.assertEqual(3, len(extensions))
        self.assertEqual([98, 99, 100], extensions)

        # We shouldn't get a trait event here because we haven't accessed the
        # extension point yet!
        self.assertEqual(None, listener.obj)

        return
    def test_assign_empty_list_no_event(self):
        """ assign empty list no event """

        a = PluginA(); a.on_trait_change(listener, 'x_items')
        b = PluginB()
        c = PluginC()

        application = TestApplication(plugins=[a, b, c])
        application.start()

        # Assign an empty list to one of the plugin's contributions.
        b.x = []

        # Make sure we pick up the correct contribution via the application.
        extensions = application.get_extensions('a.x')
        extensions.sort()

        self.assertEqual(3, len(extensions))
        self.assertEqual([98, 99, 100], extensions)

        # Make sure we pick up the correct contribution via the plugin.
        extensions = a.x[:]
        extensions.sort()

        self.assertEqual(3, len(extensions))
        self.assertEqual([98, 99, 100], extensions)

        # We shouldn't get a trait event here because we haven't accessed the
        # extension point yet!
        self.assertEqual(None, listener.obj)

        return
    def test_assign_non_empty_list(self):
        """ assign non-empty list """

        a = PluginA()
        a.on_trait_change(listener, 'x_items')
        b = PluginB()
        c = PluginC()

        application = TestApplication(plugins=[a, b, c])
        application.start()

        # fixme: If the extension point has not been accessed then the
        # provider extension registry can't work out what has changed, so it
        # won't fire a changed event.
        self.assertEqual([1, 2, 3, 98, 99, 100], a.x)

        # Assign a non-empty list to one of the plugin's contributions.
        b.x = [2, 4, 6, 8]

        # Make sure we pick up the new contribution via the application.
        extensions = application.get_extensions('a.x')
        extensions.sort()

        self.assertEqual(7, len(extensions))
        self.assertEqual([2, 4, 6, 8, 98, 99, 100], extensions)

        # Make sure we pick up the new contribution via the plugin.
        extensions = a.x[:]
        extensions.sort()

        self.assertEqual(7, len(extensions))
        self.assertEqual([2, 4, 6, 8, 98, 99, 100], extensions)

        # Make sure we got a trait event telling us that the contributions
        # to the extension point have been changed.
        self.assertEqual(a, listener.obj)
        self.assertEqual('x_items', listener.trait_name)
        self.assertEqual([2, 4, 6, 8], listener.new.added)
        self.assertEqual([1, 2, 3], listener.new.removed)
        self.assertEqual(0, listener.new.index.start)
        self.assertEqual(4, listener.new.index.stop)

        return
    def test_assign_non_empty_list(self):
        """ assign non-empty list """

        a = PluginA(); a.on_trait_change(listener, 'x_items')
        b = PluginB()
        c = PluginC()

        application = TestApplication(plugins=[a, b, c])
        application.start()

        # fixme: If the extension point has not been accessed then the
        # provider extension registry can't work out what has changed, so it
        # won't fire a changed event.
        self.assertEqual([1, 2, 3, 98, 99, 100], a.x)

        # Assign a non-empty list to one of the plugin's contributions.
        b.x = [2, 4, 6, 8]

        # Make sure we pick up the new contribution via the application.
        extensions = application.get_extensions('a.x')
        extensions.sort()

        self.assertEqual(7, len(extensions))
        self.assertEqual([2, 4, 6, 8, 98, 99, 100], extensions)

        # Make sure we pick up the new contribution via the plugin.
        extensions = a.x[:]
        extensions.sort()

        self.assertEqual(7, len(extensions))
        self.assertEqual([2, 4, 6, 8, 98, 99, 100], extensions)

        # Make sure we got a trait event telling us that the contributions
        # to the extension point have been changed.
        self.assertEqual(a, listener.obj)
        self.assertEqual('x_items', listener.trait_name)
        self.assertEqual([2, 4, 6, 8], listener.new.added)
        self.assertEqual([1, 2, 3], listener.new.removed)
        self.assertEqual(0, listener.new.index.start)
        self.assertEqual(4, listener.new.index.stop)

        return